In the field of speaker system design and implementation, many factors play a decisive role in determining, for example, what types of speakers to use, how large the speakers should be, what frequency response the speakers should have, and so on. One of the more important off these factors is the environment in which the speakers must operate. Specifically, the frequencies and amplitudes of the ambient noise surrounding the speakers-operational area must be considered.
Conventional speakers of today are utilized, for example, to present audio or audio/video advertisements in commercial and retail store environments where ambient noise levels can vary widely over time. It is known in the audio field that the intelligibility of reproduced speech or music sound in such environments, derived from an audio content signal, is strongly affected by the ratio of the volume of the reproduced sound to the volume of ambient noise. Intelligibility can therefore be enhanced by processing the audio content signal in such a manner as to vary the volume of the reproduced sound directly as a function of the volume of the ambient noise. Further, it is known in the audiology field that the intelligibility of a hearing aid microphone output signal containing both live speech and ambient noise signal components can be enhanced through a signal process that introduces both compressed gain and increasing high frequency feedback in response to decreasing amplitude of such speech and noise signal.
Such conventional speaker systems provide amplitude compensation linearly and directly as a function of the changing ambient noise. This linear compensation is a transfer function. However, the linear transfer function is non-optimal for at least retail store and other commercial environments, which commonly exhibit frequent and widely varying changes in ambient noise, since the conventionally compensated speaker output signal provides commensurately frequent and widely varying changes in sound levels that can be annoying to listeners. As such, speaker systems have been introduced providing direct, but incremental, amplitude compensation as a function of such frequent and widely varying changes in ambient noise. However, even such intelligent systems today are incapable of providing equalization among a network of speakers in, for example, a retail advertising environment and are incapable of detecting when at least one speaker of a network of speakers are inoperable, which can ultimately negatively effect equalization calculations.
As such, what is needed is a speaker system providing direct, but incremental, amplitude compensation that is capable of equalization of a plurality of speakers in a network and that is capable of sensing inoperability of speakers.